1/4" shank, .014" wire size, 4500 Max. RPM. Designed for use in restricted or hard-to-reac areas. Excellent for deburring, blending and cleaning of surfaces. Small diameter brushes are especially designed for use on portable air and electric tools Applications include deburring, blending, removal of rust, cleaning. End brushes are great for cylinder heads, pistons and valve ports, rubber and plastic flash removal, removal of rust, paint scale, tool polishing, and weld cleaning.